1. Field of the Invention
The invention is related to the field of communications, and in particular, to session admission control for PPPOE communication systems based on actual usage data.
2. Description of the Prior Art
Point-to-Point Protocol Over Ethernet (PPPOE) is a well known technique for users to access a communication system such as the Internet. PPPOE user systems exert their own bandwidth control with a throttling procedure that restricts bandwidth usage to a given range. This range is often expressed as a number of bytes per second plus or minus a percentage of the bytes per second. This percentage is referred to below as a user system control parameter.
A PPPOE user requests access to the communication system though a Remote Access Dial-Up Server (RADIUS) server. To perform admission control, the RADIUS server may check the user name and password for validity. The RADIUS server may also check the number of current users to ensure that this number remains within a total number of allowed users. This approach assumes that the total number of users would use an estimated amount of available bandwidth, so if the number of current users remains below the total, then bandwidth should be available-based on the estimate. Unfortunately, actual bandwidth usage may be higher than the estimate, and degradation in the quality of service will occur. This problem becomes especially acute in overbooking situations where users share far less available bandwidth than they would need if they all tried to use the communication system simultaneously. This typically moves the number of current users closer to the total number of allowed users and allows actual variations in bandwidth usage to seriously degrade quality of service.
Using a communication service that slows to a crawl because of poor quality of service can be extremely frustrating. With increasingly bandwidth hungry user applications, a technique is needed to better provide quality of service to PPPOE users. Some non-PPPOE communications systems, such as Asynchronous Transfer Mode (ATM) systems, use actual usage data for admission control, but such techniques have not been effectively implemented for PPPOE user systems.